Pattern Making Process

Posted on July 8, 2019March 18, 2026 by admin

Development of patterns is the first step in the casting process. Patterns can be re-used to make more moulds and, if looked after, can last for many years making thousands of moulds.

For producing a mould or impression of desired shape in moulding sand, one needs to have a wooden or metallic pattern similar to the shape of the mould. The art and science of designing the pattern is called pattern making.

Common Metals that are used for creating patterns are –

Wood
Metal
Plaster
Plastic

Types of Pattern-Making Process

The type of patterns selected for a particular casting depends upon many factors such as type of moulding process, number and size of casting difficulty of moulding on account of design or typical shape of casting. The most common types of pattern are listed and described below:
(a) Solid or Single Piece Pattern
(b) Split Pattern
(c) Gated Pattern
(d) Sweep/Skeleton Pattern
(e) Match Plate Pattern

(a) Solid or Single Piece Pattern

The one piece or single pattern is the most inexpensive of all types of patterns. This type of pattern is used only in cases where the job is very simple and does not create any withdrawal problems. It is also used for application in very small-scale production or in prototype development. This type of pattern is expected to be entirely in the drag and one of the surface is is expected to be flat which is used as the parting plane. A gating system is made in the mold by cutting sand with the help of sand tools.

(b) Split Pattern

Split or two piece pattern is most widely used type of pattern for intricate castings. It is split along the parting surface, the position of which is determined by the shape of the casting. One half of the pattern is molded in drag and the other half in cope. The two halves of the pattern must be aligned properly by making use of the dowel pins, which are fitted, to the cope half of the pattern. These dowel pins match with the precisely made holes in the drag half of the pattern.

(c) Gated Pattern

Gated patterns are a group of patterns in which multiple castings are connected through a common gating system. In this type, runners and gates are integrated directly into the pattern, allowing molten metal to flow into several mould cavities simultaneously. This method increases production efficiency and reduces moulding time, making it highly suitable for mass production. Gated patterns are commonly used when producing small components in large quantities.

(d) Sweep/Skeleton Pattern

Sweep and skeleton patterns are used for producing large and symmetrical castings, where making a full solid pattern would be expensive and impractical.

A sweep pattern consists of a template (usually wooden) that is rotated around a central axis to generate the desired mould shape in sand. It is commonly used for circular or cylindrical shapes like pipes and tanks.

A skeleton pattern, on the other hand, is a framework that outlines the shape of the casting. The mould is formed by filling sand around the framework and finishing it manually. These patterns are economical and suitable for large castings produced in small quantities.

(e) Match Plate Pattern

Match plate patterns are used for high production work and are ideal for machine moulding processes. In this type, both halves of the split pattern are mounted on opposite sides of a single plate (called the match plate). The gating system, including runners and gates, is also attached to the plate.

This arrangement ensures accurate alignment of the cope and drag sections, reduces moulding time, and improves productivity. Match plate patterns are widely used in automated foundries for producing large numbers of identical castings with high precision.

How to install BIC Hubless Pipes & Fittings

Posted on May 20, 2019 by admin

This is a step-by-step guide for connecting BIC hubless pipe and fittings with BIC couplings. These suggestions are based upon accepted international industry standards and practices.

Important Points to Note

Ensure that the pipe ends have been cut straight and clean.
To prevent movement, pipes and fittings should be suitably braced by the use of blocks, rodding or other suitable methods wherever necessary.

Coupling Material

Coupling Shield: SS304
Rubber Gasket: EPDM

The Hubless Couplings gaskets are made of EPDM rubber conforming to IS 15905:2011. Chemical characteristics of EPDM assure that the gasket will not decay or deteriorate from contact with effluents in the pipe, or chemicals in the soil or air around the pipe.

BIC SS304 Coupling with EPDM Gasket

Joining Procedure

Loosen screws, separate SS304 shield and EPDM rubber gasket.
Insert one spigot into the gasket and slip the shield over.
Insert spigots into the gasket from both sides and ensure they sit evenly and firmly on the rim inside.
Move the shield over the gasket and screw alternately to a tight fit.

Defects in castings – Ductile & Grey Cast Iron

Posted on May 10, 2019 by admin

Defects during the casting process are not uncommon. Under practical conditions, all casting products contain voids, inclusions and other imperfections which contribute to a normal quality variation. Such imperfections begin to be regarded as true defects or flaws only when the satisfactory function or appearance of the product is in question: consideration must then be given to the possibility of salvage or, in more serious cases, to rejection and replacement.

Classification

The general origins of defects lie in three sectors:
1. the casting design,
2. the technique of manufacture–the method,
3. the application of the technique–‘workmanship’.

Standardization and optimisation of all aspects of the production technique offers the best way-out against such troubles. More specific precautions can be taken in those cases where there is a known susceptibility to a particular defect, whilst the radical approach of design modification may need to be considered in the extreme cases which do not respond to changes in foundry technique. It should be clear that any approach to the elimination of casting defects must be on an economic basis.

1. Shaping faults arising in pouring.
2. Inclusions and sand defects.
3. Gas defects.
4. Shrinkage defects due to volume contraction in the liquid state and during solidification.
5. Contraction defects occurring mainly or wholly after solidification.
6. Dimensional errors.
7. Compositional errors and segregation.

Significance of analysis of defects

Casting defects, whatever their cause, cannot be considered in isolation; their significance can only be established in relation to the function of the casting. Behaviour under service stresses and environment is in most cases the important reason behind the appearance.

What are the reasons of their occurrence? The first one is the
quality and the parameters of moulding and core mixtures. Number of the
defects was affected by temperature and humidity of ambient air, both in
store yards and in moulding mixture preparation shop. Consequently, it is
reflected in moisture content of silica sand and moulding mixture. This fact
can affect the quality of moulding and core mixtures and their prone to
disintegration by molten metal flow.
The second one is the presence of complicated design of the cavity in the mould,
containing thin walls, profiles, runners. From this fact follows the necessity
to design parameters of moulding mixtures from the mould complexity
point of view.
The third one is chemistry and pouring temperature of molten metal.
Viscosity of poured metal is extremely important.

India’s Perspective: Global Cast Iron Market

Posted on April 12, 2019 by admin

Amidst all the political uncertainties in Europe and US, the overall scenario of global cast iron market is growing in the positive direction. The US GDP growth rate is over 2% and that has increased consumption and demand of raw materials for infrastructure.

Grey cast iron is one of the most widely used castings and typically contains between 2.5% and 4% carbon, and between 1% and 3% silicon. The market potential of heavy grey iron castings is good and expected to be bright in future. These castings are required by sugar mills, general engineering works and mini-steel plants. The demand for such castings is increasing continuously due to rapid industrialization. Increased urbanization too is fueling the requirement for construction castings such as manhole covers, pipes and pipe fittings. Amidst all the political uncertainties in Europe and US, the overall scenario of global cast iron market is growing in the positive direction.

Export Quantity Value of Grey Iron is slowly growing after the Recession in 2008

Wide use of grey cast iron:

The versatile nature of cast iron makes it an excellent material for various companies to employ various moulding techniques and come up with a new range of products. The fluidity of liquid grey iron and its expansion during solidification is due to the presence of graphite. This property makes it ideal for the production of intricate castings. Shrinkage rate of grey cast iron is lesser as compared to ductile iron due to the percent of carbon content. With proper control of the carbon and silicon contents and the cooling rate, the formation of iron carbide during solidification is suppressed entirely, and graphite precipitates directly from the melt as irregular, generally elongated and curved flakes in an iron matrix saturated with carbon.

Quality attributes of grey cast iron in global cast iron market:

The presence of graphite flakes in the microstructure is responsible for its superior characteristics. It has more carbon content than the steel and therefore it has more than one microstructure. The higher carbon content of cast iron means that it solidifies as a heterogeneous alloy.

The iron & steel casting market is expanding steadily due to robust growth in construction and mining industries, especially in Southeast Asia and Eastern Europe. Increasing demand for iron & steel casting in automobile and electrical industries is anticipated to propel the growth of the market.

The development of state-of-the-art foundries was necessary to provide consistent, high quality castings. Castings from a highly automated Chinese foundry are 20% more expensive
than a hand foundry but are necessary for applications requiring repeatability and quality.

However, the recent changes in the labour and environmental laws in China accompanied with economic slowdown in US has compelled many small and medium scale businesses in US and Europe to import more from India. Poor air quality has forced the government to take a harder look at the industry as a contributor to pollution. This has led to an accelerating rate of iron ore mine closures in China. This has helped to improve the competitive edge of Indian foundries.

Having said that, Chinese manufacturers have the ability to respond to changes in demand with moderate‐to‐large changes in the quantity of shipments of cast iron fittings to the U.S. and Europe market. The main contributing factors to this degree of responsiveness of supply are the availability of unused capacity and inventories.

Traditionally, US and Europe markets are the largest importers of iron ore as well as cast iron and steel. However, there is a strong economic signal from the Middle East as well as from the ASEAN countries that has diversified the import market.

Germany, which is presently the 4th largest economy in the world, has a huge demand as their economy are growing at a good pace. They are considered to be the market leaders in high-end engineering goods so their OEM always look out for precision products with super-build quality.

Cast Iron: CI Composition, Properties and Products

Posted on January 29, 2019 by admin

Pig Iron is the intermediate iron product between smelting iron ore and usable cast iron products. Grey Cast iron (CI) is made when pig iron is re-melted in small cupola furnaces (similar to the blast furnace in design and operation) and poured into molds to make castings. Cast Iron is considered as an alloy of iron with greater than 2% carbon, and usually with more than 0.1% silicon and there are are 3 other important types of cast iron (CI products) apart from grey cast iron.

The presence of flake graphite in the silicon-iron matrix make grey iron castings a unique material. The presence of graphite, the distribution pattern and the length of the flakes determine the strength and quality of cast iron.

Primarily there are 4 types of cast iron –

Grey Cast Iron
Ductile Iron
Malleable Iron
White Cast Iron

We will discuss more about Grey Cast Iron here –

In gray iron, slower solidification produces a larger graphite flake size. A slower cooling of the casting will produce a lower hardness in the metallic matrix.

Fatigue properties
Damping properties

The properties of grey iron can be determined by the amount of additional elements in the grey iron :

Cast iron contains small percentages of silicon, sulphur, manganese and phosphorus. The effect of these additional elements on the cast iron are as follows:

Silicon: About 3% of silicon can be present in cast iron. It provides the formation of free graphite which makes the iron soft and easily machinable.
Manganese: It makes the cast iron white and hard. It is often kept below 0.75%. It helps to exert a controlling influence over the harmful effect of sulphur.
Phosphorus: It aids fusibility and fluidity in cast iron, but induces brittleness. It is rarely allowed to exceed 1%. Phosphoric irons are useful for casting of intricate design and for many light engineering castings when cheapness is essential.

Cast Iron Products: Quality Control and Management

Posted on January 29, 2019 by admin

Quality control methodology has undergone a long period of change, involving a broadening of the subject to enhance many more aspects of the production process and product than were traditionally considered. These changes have had major effects in the field of internal management organization, as well as in the commercial relationships involved in the procurement of castings.

Casting defects can negatively impact the profit margin of the company. There are instances such as rework costs or casting scrap costs that not only affect financial state of the company but also affect customer services. However, in many cases, the casting defects may appear at the machining stage, at the assembly stage or during use of the component. The resultant value added costs and warranty costs may sometimes be passed on to the foundry by their customers.

Let’s take a look at the kind of defects and how they can be identified.

Tests for defects in the surface zone

Cracks and other flaws communicating directly with the surface of the casting can be detected using techniques including penetrant methods, chemical etching and oil and chalk testing. The penetrant methods are based on the use of fluids to permeate and highlight defects by increasing their contrast and are helpful in establishing the soundness and integrity of thin walled castings in cases where pressure testing is difficult to execute. If there is any seepage, then it can be easily observed.

Dye penetrant testing

The surface of the casting is treated with a dye solution based on a low viscosity solvent which is applied by brush or aerosol spray or the casting can be entirely immersed in a tank of solution; the casting is then thoroughly rinsed and dried. After a time, seepage of residual fluid occurs from cracks and other narrow surface defects to produce a visible stain.

Oil and chalk testing

This long established technique uses paraffin oil as the medium. The casting is treated, usually by immersion, with heated paraffin; it is then rinsed in detergent solution and water and dried. Using a low pressure air dispenser the surface is coated with dry powdered chalk, which becomes marked after a time by seepage of paraffin from cracks or porous zones.

Chemical etching

Very fine surface cracks and similar defects may be masked by a thin layer of metal resulting from superficial plastic deformation. This can occur in shot blasting, in fettling or even in the machining of a casting. The masking layer may consist of oxide scale formed in heat treatment.

A simple analysis of casting defects

For the characteristic criterion of quality level measuring, it is assumed quantity of defects in one year. The first step of analysis is the assessment of process by means of Ishikawa’s diagram. Ishikawa’s diagram – diagram of cause and effect, or “fish bone” diagram – makes possible identification of sources of problems formation, helps quality a sequence of causes and makes easy problem solution (SIEKANSKI K. 2002).

Ishikawa Diagram_BIC

Fig. 10.1 Part of Ishikawa´s diagram for problem of non-conformances formations in process of casting products.

Source: https://tulip.co/blog/lean-manufacturing/fishbone-ishikawa-diagram-for-root-cause-analysis/

BIC at Engineer Training Programme on Cast Iron Soil Pipes and Fittings

Posted on January 2, 2019April 9, 2024 by admin

December 28, 2018, was a special day for BIC. Our North India Sales Head, Mr Gaurav Gupta, had the honour of being invited by the Department of Water Supply & Sanitation, Punjab to educate newly appointed Junior Engineers (JEs) on the uses as well as quality standards of cast iron soil pipes and fittings.

The induction training programme was attended by 180 JEs along with veteran Executive Engineers and Chief Engineers. Gaurav’s lecture focussed mainly on what engineers should look out for when selecting and evaluating cast iron soil pipes and fittings as per IS 1729:2002. The considerations of quality, designs, special use cases and manufacturing techniques were brought to light. One of the most interesting points that was discussed was the importance of deep as well as shallow seals in Nahani Traps and P-Traps. The design of these seals is imperative in preventing foul odour, keeping away pests and avoiding clogged toilets.

BIC has a legacy of being the premier supplier of this range of cast iron pipes and fittings. It is our focus on maintaining these design considerations and quality standards that have enabled us to be a market leader in IS 1729:2002 products. We are proud to be exporting these items to various countries across the globe as well.

Training the new generation of engineers who serve the Government of India is truly an honour for us and we hope to play our part in the development of the country.

BIC Attends Rajkot Machine Tools Exhibition

Posted on December 10, 2018 by admin

Rajkot Machine Tools Exhibition

One of BIC’s mission statements is to continually explore leading technology and adopt them considering key factors of quality improvements, productivity gains, environmental impact and profitability. Following this yardstick, two engineers from our company visited the 7th Rajkot Machine Tools Show (RMTS) on 28^th November 2018.

With increasing global demand, it has become imperative for all industries to upgrade their equipment and utilize robotic mechanization to its fullest. The cast iron manufacturing industry is no different. Traditionally, a lot of the Howrah foundries have relied on manual labour. This was good for a time when cheap labour was readily available. However, with increasing purchasing powers of the Indian household, finding skilled labourers willing to work in foundries is becoming increasingly difficult. Industrial automation is no longer a choice. It is the only way forward to even stay relevant.
At RMTS, some cutting-edge Indian technology was at display aimed at increasing productivity manifold while simultaneously reducing the probability of errors. Automated pipe cutting machines, IoT powered CNC and VMC machines, laser tools, Industry 4.0 setups and AI-powered software were some of the highlights BIC has been manufacturing custom cast iron industrial parts for decades now. As new customers are acquired, the requirements too change. In order to cater to larger volumes and narrower tolerances, a decision was made on the spot at the exhibition to purchase some of this equipment.
As these equipment are assembled and delivered to our facility in Kolkata, we at BIC are thrilled to be growing. We are excited to be serving our existing customers faster and better, and at the same time taking on new challenges with new relationships.

Extracting the Most from the Casting Project

Posted on September 6, 2018March 18, 2026 by admin

Partnering with the right supplier foundry is crucial to get the most from your casting project. Good planning and execution of the same, pave a path to castings compatible with your requirements. In fact, it needs a conjugated effort from a competent supplier foundry and the consumers to enjoy the benefits of a project. However, the challenge is to locate the top-notch supplier foundry as it demands acute research and an intense understanding of your component.

How to Start a Project with a New Foundry?

To start with a new project with a Ductile Iron Foundry India, it is crucial to understand whether it is proficient enough to produce the outcome as per the quality standards and listed specification. Once you locate the best foundry from the crowd and have the castings of ferrous and non-ferrous origins ready for the production, you may ask the shortlisted foundries to quote a price for your project. Not only this allows you to understand the capability and experience of the vendors but also enables you to take the decision as per your budget. Never close on a particular vendor before analyzing the prospects and quotations. This ensures you seal the deal with the best foundry for a cost-effective contract.

Is Budget the Exclusive Decision-Making Criterion?

Once you select the most favorable and affordable foundry, it is now time you analyze the other aspects of the quotation, which includes processing requirements, specifications, and exclusions of the drawings. Along with it, you must also analyze the other criteria like the tolerance, delivery, tooling requirement, delivery, and experience of the supplier foundry. This help complete the casting project with revised delivery routine, tolerance recommendations, reduced machine works, and enhanced reliability.

Primary Criteria to Get the Most from the Casting Project

Never approach a stereotypical path, to attain a fruitful outcome of the casting project. Rather, look for the core points to get the most from the same, which are as follows:

The volume of casting needed for the short and long-term demands.
Casting designs with proper drawings, models, samples, and images.
Specifications of the raw materials.
Inspection of the probable outcome and ensure a balance between requirements and specifications.
Details of the casting requirements that include weight, finish, and materials used.
Schedule of delivery according to the casting.
Details of the pattern.

Establishing a Coordinating Relationship with the Consumers for the Success of the Casting Project

If you believe the aforementioned criteria are enough to fetch the most desired casting project, you are under the wrong notion. Scrutinize the customer requirements with utmost importance through a proper communication to build a strong foundation for your project. Some of the best ways to establish a fruitful communication, while not relating to the standard inquiry are the back charge policy, expediting the procedure, casting return policy, as well as the sophisticated controls. Once you get your hands on the proper information, not only you succeed in creating an open relationship between the consumer and supplier foundry but also lead to a seamless accomplishment of the casting project. This will help you overcome all the hurdles associated with the casting projects so that you can enjoy the outcome without any exception.

Once you succeed in overcoming the challenges of quality, budget, and communication in the path of creating a standard casting project, the success is inevitable. Don’t restrict to explore the aforementioned criteria and delve into the niche to get the most from the project.

Types of Pig Iron and Its Applications for Casting Requirements

Posted on June 7, 2018March 18, 2026 by admin

Pig iron is an output obtained as a result of the process of manufacturing iron. Fuel coke with high carbon is utilized in order to heat the iron ore. This results in the production of pig iron which is high in carbon content. The cold pig iron is known as merchant pig iron, which is cast into blocks or ingots. These are then sold to the ferrous as well as steel casting industries in the form of feed stock. There are three types of merchant pig iron, which are as follows:

Basic pig iron– This is used in electric arc furnace for the purpose of steel making.
Foundry pig iron– This type of pig iron is also known as haematite pig iron and is used in cupola furnaces for grey iron castings.
High purity pig iron– This is synonymous to nodular pig iron and is used for producing ductile iron castings, which is also known as SG or Spheroidal Graphite. This is used by the manhole cover manufacturers.

Attributes and Application of Foundry Pig Iron for the Grey Iron Casting

This type of pig iron is produced from the specific sources of iron ore. Due to the stable physical as well as chemical analysis it enables the variability of melting and a robust control over the composition of final casting. This eradicates the need for the high-priced casting requirements like heat treatment. This category of pig iron is used in the genres like machine tools, general engineering, and automotive parts manufacturing. Creation of pearlite in the final casting is promoted because of the high iron content on the pig iron.

The application of the foundry pig iron seamlessly promotes the formation of graphite, depletes the primary chill, and enhances machinability. This is highly beneficial for the thin-walled castings. The bulk density of this pig iron is also on the higher side in comparison to the scrap, which needs a lesser space for the storage, and reduced time for charging. In fact, the energy consumption is also reduced remarkably due to higher carbon content. Hence, this type of pig iron is highly beneficial for the manufacturing industries specifically for the casting needs.

Attributes and Application of High Purity Pig Iron for the Ductile Iron Casting

This type of pig iron is also known as HPPI and is characterized by its lower contents of sulfur, phosphorus, and manganese. The presence of the other metal impurities is also negligible that makes the iron highly desirable in various sectors. The application on HPPI can be mainly found in the casting components of the automotive, energy, and engineering industries. There are various advantages associated with HPPI that contributes to the successful ductile iron casting, which are as follows:

The undesirable elements in the melt are diluted that aids in the depleted cost of scrap.
The predictable and stable composition of the iron helps achieve better control over the final composition of casting, which leads to an enhanced mechanical output of the casting.
It demands lower storage space and lesser charge buckets.
Lower formation of rust leads to the depleted volume of slag.
Due to the chemical combination of carbon content, the casting is achieved easily with lower consumption of energy.
The reduced consumption of power and rapid melting leads to the lesser power consumption in the induction furnace.

Hence, the implementation of HPPI in diversified casting needs help reduce the net investment.